The work to date has focused on establishing and validating an assay for the enzyme(s) that convert estrogens to their catechol form ("estrogen catecholase(s)"). The assay will be used 1) to determine the anatomical sites in brains of rats where catechol estrogens are formed, 2) whether they are formed in neurons or in glial cells and 3) if there are changes in the level of activity of "estrogen catecholase(s)" with changes in reproductive status of the animal. The influence of catechol estrogens on sexual differentiation of rat brain is also being evaluated. Studies are also planned to use catecholaminergic neuronal cells in tissue culture to determine whether adding catechol estrogens to the culture medium alter various indices of catecholaminergic function, including tyrosine hydroxylase, catechol-O-methyltransferase, monoamine oxidase, the uptake of tyrosine hydroxylase and of catecholamines.